for(1)

Name

Description

The shell command interpreters csh(1), ksh(1), and sh(1) have special built-in commands. The commands case, for, foreach, function, if, repeat, select, switch, until, and while are commands in the syntax recognized by the shells. They are described in the Commands section of the manual pages of the respective shells. The remaining commands listed in the table below are built into the
shells for reasons such as efficiency or data sharing between command invocations. They are described on their respective manual pages.

Command

Shell

alias

csh, ksh

bg

csh, ksh, sh

break

csh, ksh, sh

case

csh, ksh, sh

cd

csh, ksh, sh

chdir

csh, sh

continue

csh, ksh, sh

dirs

csh

echo

csh, ksh, sh

eval

csh, ksh, sh

exec

csh, ksh, sh

exit

csh, ksh, sh

export

ksh, sh

false

ksh

fc

ksh

fg

csh, ksh, sh

for

ksh, sh

foreach

csh

function

ksh

getopts

ksh, sh

glob

csh

goto

csh

hash

ksh, sh

hashstat

csh

history

csh

if

csh, ksh, sh

jobs

csh, ksh, sh

kill

csh, ksh, sh

let

ksh

limit

csh

login

csh, ksh, sh

logout

csh, ksh, sh

nice

csh

newgrp

ksh, sh

nohup

csh

notify

csh

onintr

csh

popd

csh

print

ksh

pushd

csh

pwd

ksh, sh

read

ksh, sh

readonly

ksh, sh

rehash

csh

repeat

csh

return

ksh, sh

select

ksh

set

csh, ksh, sh

setenv

csh

shift

csh, ksh, sh

source

csh

stop

csh, ksh, sh

suspend

csh, ksh, sh

switch

csh

test

ksh, sh

time

csh

times

ksh, sh

trap

ksh, sh

true

ksh

type

ksh, sh

typeset

ksh

ulimit

ksh, sh

umask

csh, ksh, sh

unalias

csh, ksh

unhash

csh

unlimit

csh

unset

csh, ksh, sh

unsetenv

csh

until

ksh, sh

wait

csh, ksh, sh

whence

ksh

while

csh, ksh, sh

Bourne Shell, sh, Special Commands

Input/output redirection is now permitted for these commands. File descriptor 1 is the default output location. When Job Control is enabled, additional Special Commands are added to the shell's environment.

In addition to these built-in reserved command words, sh also uses:

:

No effect; the command does nothing. A zero exit code is returned.

.filename

Read and execute commands from filename and return. The search path specified by PATH is used to find the directory containing filename.

C shell, csh

Built-in commands are executed within the C shell. If a built-in command occurs as any component of a pipeline except the last, it is executed in a subshell. In addition to these built-in reserved command words, csh also uses:

:

Null command. This command is interpreted, but performs no action.

Korn Shell, ksh, Special Commands

Input/Output redirection is permitted. Unless otherwise indicated, the output is written on file descriptor 1 and the exit status, when there is no syntax error, is zero.

Commands that are preceded by one or two * (asterisks) are treated specially in the following ways:

Variable assignment lists preceding the command remain in effect when the command completes.

I/O redirections are processed after variable assignments.

Errors cause a script that contains them to abort.

Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a variable assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.

In addition to these built-in reserved command words, ksh also uses:

* : [ arg . . . ]

The command only expands parameters.

* .file [ arg . . . ]

Read the complete file then execute the commands. The commands are executed in the current shell environment. The search path
specified by PATH is used to find the directory containing file. If any arguments arg are given, they become the positional parameters. Otherwise, the positional parameters are unchanged. The exit status is the exit status of the last
command executed. the loop termination test.